Laminated products and adhesive compositions of matter



Patented July 17, 1951 LAMINATED PRODUCTS AND ADHESIVE COMPOSITION 8 OF MATTER Charles I. Mlghion, Wilmington,

Dcl., alsignor to E. I. du Pont de Nemours In Company, Wilmington, Del., a corporation of Delaware No Drawing. Application November rial No. 028.100. In Canada June 11, 1945 18 Claims. (01. 154-48) This invention relates to novel compositions and their use as adhesives, particularly in the bonding of textile material to rubber and other elastomers. The term elastomer" is a generic term for all substances having the properties of natural rubber. reclaimed rubber and artificial rubber-like materials which are ordinarily termed synthetic rubber."

This application is a continuation-in-part oi my copending application Serial No. 543,202, filed July 1, 1944, now abandoned.

Many compositions have been suggested for use in the art of lamination, including combinations of rubber latex or reclaimed rubber dispersions with resinous materials. However, in certain types of lamination such as the bonding oi rayon to rubber in the making of rubber tires and the like, and the bonding of rubber to metal, the adhesives heretofore suggested for use have not been completely satisfactory and, in the art of lamination generally, there is considerable room for improvement with respect to the type of adhesive to be used. There is special need for improved adhesives in the bonding of synthetic fibers such as viscose rayon and nylon fibers to rubber and the like in order to eflect a tenacious bonding between the fibers and rubber, both at normal and at elevated temperatures.

It :1 object of this invention to provide new and improved compositions of matter. A further object of the invention pertains to the production of improved adhesives. A special obiect oi this invention is concerned with improving the adhesion between rayon and nylon cords and fabrics to rubber, particularly in the manufacture or reiniorced rubber structures such as'tires. Other objects will appear hereinafter.

The objects of the invention have been attained by the discovery of new compositions comprising blends of copolymers of vinyl pyridines and diene hydrocarbons, with heat convertible phenol-aldehyde resols. In utilizing the new compositions for lamination, the blend oi copolymer and thermosettlng resol is preferably prepared in an aqueous system, is applied to the surface of at least one of the objects to be adhered, the treated surface is brought into contact with the second component of the lamination and the resulting composite article is treated to convert the resin to the infusible state. Where the new adhesive compositions are used in the manufacture of rubber tires. they are preferably applied to the tire fabric, the rubber stock being then combined with the fabric and subjected to vulcanlzlns wn ions. the resin being converted at tltietevulcanizing temperature over to the infusible B The following examples illustrate preferred modes of applying the principles of the invention and parts, proportions and percentages are by weight unless otherwise specified:

A mixture of parts of butadiene and 25 parts of alpha-vinyl pyridine is emulsified in 157 parts of an aqueous solution containing 4 parts of sodium oleate, 0.5 part oi sodium hydroxide, 1 part of a formaldehyde/sodium naphthalene sulfonate condensation product, 1 part of potassium persulfate and 0.1 part of potassium ferricyanide. One half we) part of lauryl-mercaptan is added and the emulsion is heated for twenty hours at 40 C. in a sealed. glass lined vessel equipped for emcient agitation. The resulting smooth latex is treated with an antioxidant consisting of 2 parts of a phenyl-alpha-naphthylamine and diphenylamine (55:45) mixturedispersed in water. The dispersion contains about 40% solids.

One hundred ten (110) parts of reso'rcinol and 225 parts of a 40% formaldehyde solution are dissolved at 25 C. in 475 parts of water to' give a 25% resol solution.

The above materials are used in formulating an adhesive composition as follows:

To 100 parts of a 15/25 butadiene/vinyl pyridine latex prepared as in A, 100 parts of water, parts of a resorcinol/formaldehyde resol solution prepared as in B, and 0.6 part of sodium hydroxide (as a 10% aqueous solution) are added. The resulting blend is applied to a weighed strip of a square-woven nylon fabric one inch wide and five inches long. the fabric being dried for five minutes at (2., weighed to determine the adhesive loading, 1. e. per cent dried adhesive on the basis of unimpregnated fabric, and placed adhesive side down on an unvulcanized but compounded natural or synthetic rubber stock. Formulasforthestocksusedmaybefoundinthe appended Table IV. The composite is placed in a mold and heated at to C. until the rubber is vulcanized and the adhesive is heatconverted. The composite is then removed from them mold, cooled and the bond strength determined by measuring the pull in pounds per inch aldehyde resin blend as an blends with a 75/26 butadiene/etyme interpolymer, 70/30 butadiene/serylonitrile oopoiymer and polychloroprene latex.

IXAIIPIIII Abiendof400partsoi'a'l5/35 hutadiene/yinyl pyridinelatexpreparedasdeseribedinAofflxampieLdoflpai-tsotwateranddpartsoiam b aqueous solution of sodium dibu'tyl dithioearbamatewithdspartsotresereinoLiflopai-tsof watenljpartsoisodiumhydmuideandsopans oi'aa'lqb aqueous formaldehrdesolutiouistested asanadhesivetorbondimrubbertonylonand torayonasdescribedincotmmplel. Theresultswithrespeettonylonareshowninitemfi oiTabieI;bondsoi25amil0pmmdsperinch at 25 and 100 C.respectivelywere obtained betweenvlseoserayonandrubbsrwith 11% adhesiveloadins.

A blend 01' 100 parts of a /10 butadiene/viny 4 otwaterandipartotwse aqueoussodiumdibutyi dithiocarbamate with partsoireeoroinol, 0.8 part of sodium hydroxide, parts or 81% aqueous 1 solution and 100 parts or wateristestedasanedhesiveasdesciibedinmxampleI-c. Theresuitsareshownin'rabiel.

item I.

A blend of a 00/5 hutadiene/vinyi pyridine oopolymsrlatuwmr dasinmampleI-Awitha obtainedareshownin'iabieLitems.

Ablend100partsoi'a26filatexoi substituting isoprene tor Butadiene and employingapolymerisationeycieoidohoursateo'a, l00partsotwaterand1partota00$6 aqueous solution of sodium dibutyl dithiocarbamate with llipartsoiresoroinoLSOpartsoi'S'li aqueous iormaldehyde solution. and 0.3 part of sodium hydroxideandlwpartsoi'wateristestedasan adhesive as described in Example 143. At 0% adhesiveioadinmbondsashlshesfiflpoundsper inchandlwpoundsnerinchareobtainedbetween nylon and rubber and a /25 butadiene/styrene interpolymer respeetivelyat 25 C.

m Atl00c..theadhesionueeedsthetearstrengths oi the uicanisates.

sosnmo or NYLON name T0 auansna s Bonds,

Adhesive fig? so. mo l I 1.5 a so IednGnmpIeI-B) a g; s a I 4 I g o) 13 M s n m""'"o nan-mm resin (:1 g :3; 1 w Illa! H I" a 1s m 3 an an Q s 11:11:

0B-8haeunmushlsmthetlembbermmd a pwosimtslyaanm v aeerldlnztn 8. Patent No.

I olnsslun'hlslnndatluf "Ne M failure; rubber stock tors.

parts oi wateris tested as an adhesive as dein Table 1. item.

a blend of parts otan ss/1s butediene/ inyl pyridine eopolymerlatesmaredasdesm-ibedin scribed in Example I-O. "I'heresultsare shown Examples! to V! are with the use. togetherwithresoluotoidienesand alpha-vinylpyridineu-vlnyi pyridine) whiehhas the structural formula:

'3 f nix Lakes.

aether with resale, this form of the invention be- Example LA for the 75/20 100 parts II in: found to give excellent results. 5-etbyl-2- vinyl pyridine has the structural formula:

-ethyl-2-vinyl pyridine may be prepared as follows: 5-ethyl-2-methyl pyridine (collidine) is prepared from paraldehyde and ammonia in a manner similar to that described in British Patent No. 146,689 and German Patent No. 349,184. By the treatment of 5-ethyl-2-methyl pyridine with formaldehyde according to the methods employed by Loilier and Grosse [Berichte 40, 1325 (1907)] for preparing 2(beta-hydroxyethyl) pyridine from alpha-picoline, 5- ethyl-2-(beta-hydroxyethyl) pyridine is formed, this latter compound being dehydrated to 5- ethyl-2-vinyl pyridine by distillation from solid sodium hydroxide in a manner similar to that described by Ladenburg [Berichte 22, 2505 (1089)] for the dehydration of 2(beta-hydroxyethyl) pyridine to 2-vinyl pyridine.

EXALIPLEVII A mixture of 90 parts of butadiene and parts of 5-ethyl-2-vinyl pyridine is emulsified in 152 parts of an aqueous solution containing 4 parts of sodium oleate, 2 parts of sodium rosinate, 0.8 part of sodium hydroxide, 1 part of a formaldehyde/sodium naphthalene sulfonate condensation product, 1 part of potassium persulfate and 0.15 part of potassium ferricyanide. One (1) part of dodecyl mercaptan is added and the mixture in a sealed glass container is agitated end-overend for sixteen hours in a water bath maintained at 40 C. The resulting smooth latex, containing about 35% solids, is treated with antioxidant consisting oi 3 parts of phenyl-alpha-naphthylamine and diphenylamine (55:45) mixture dispersed in water.

A blend of parts of the 90/10 butadiene/5- ethyl-2-vinylpyridine copoiymer latex described above and 20 parts of distilled water, with a solution of 2 parts of resorcinol, 1 part of a 37% aqueous formaldehyde solution, 1.1 parts of an aqueous 10% sodium hydroxide solution and 20 parts of water, is applied after aging at room temperature for twenty hours to a strip of a squarewoven nylon fabric, one inch wide and five inches long. The impregnated fabric is dried ten minutes at 135 C. and placed adhesive side down on an unvulcanized but compounded natural or synthetic rubber stock. Formulae for the stocks used may be found in the appended Table IV. The composite is placed in a mold and heated under 150 pounds per square inch pressure until the rubber is vulcanized and the adhesive is heatconverted. The composite is removed from the mold, cooled, and the bond strength determined by measuring the pull in pounds per inch necessary to separate the rubber and the fabric. The results of this test and of tests of similar adhesive compositions described in the examples following are shown in Table II.

EXAMPLE VIII Item 2 in Table 11 shows the results obtained in adhesive tests of a blend of an 85/15 butadiene/fiethyl-2-vinyi pyridine copolymer with the same resorcinol/formaldehyde resol and the same ratio of copolymer to resol as in Example VII. The copolymer was prepared in a manner similar to that of Example VII-A.

Item 3 in'i'able II shows the results of similar tests of a blend of an 80/20 butadiene/5-ethyl-2- vinyl pyridine eopolymer prepared in a manner similar to Example VII-A, with the same resorcinol/tormaldehyde meal in the same eopolymer to resol ratio.

Item 4 in Table II shows the results of similar tests with a 15/25 butadiene/5-ethyl-z-vinvl pyridine copolymer in the same eopolymer to resolratioasinExampleVlIandwiththesame resol.

EXAMPLE 1X A mixture of 48 parts-of isoprene and 12 parts of 5-ethyl-2-vinyl pyridine is emulsified in 96 parts of an aqueous solution containing 2.4 parts of sodium oleate, 1.2 parts of sodium rosinate, 0.48 part of sodium hydroxide, 0.6 part of a formaldehyde/sodium naphthalene sulfonate condensation product, 0.6 part of potassium persuliate and 0.09 part of potassium ferrieyanide. Six-tenths (0.6) part of dodeeylmercaptan is added and the mixture, in a sealed glass vessel, is agitated end-over-end for thirty-six hours in a water bath maintained at 40 C. The resulting smooth latex, containing about 35% solids, is treated with an antioxidant consisting of 1.8 parts of a phenylamine (55:45) mixture dispersed in an equal weight of water.

A blend of 20 parts of the 00/20 is isoprene/5- ethyl-z-vinyl pyridine copolymer latex described above and 20 parts of water with a solution of 2 parts of resorcinol, 1 part of a 37% formaldehyde solution, 1.1 part of an aqueous 10% sodium hydroxide solution and 20 parts of water is applied to nylon fabric and tested as an adhesive exactly as described in Example VII. The results are shown as item 5 in Table II.

EXAMPLEX naphthylamine and dlphenyiamine mixture (55:45) dispersed in an eq al weight of water.

A blend of 25 parts of the /15 butadiene/5- ethy1-2-vinyl pyridine eopolymer latex described above and 15 parts of water with a solution of 2 parts of resorcinol, 1 part of a 37% formaldehyde solution. 1.1 parts 01' an aqueous 10% sophenyl-alpha-naphthylamine-di- Alflllobutadieneli-ethyl-fl-vlwlmidineeopolymerispreneredinsmsnnersimflsrtothst o! a. phenyl-elphe-naphthyismhae and dinhenyl- WW mm W Mm WWW theseadhesivetestewithnyloniebriesreshown asitem'lin'rablen.

A solution 01 8 Perl: 01' 37% tomaldehyde'solu n The composition described in Example x-c sbovewaseveluetedinthelsmemesmsnent sifltsai'eshownssltemllln'labien.

aqueous 10% sodium hydrotide' parts of a 90/10 buhdiene/S-vhwlwrldlne eomannerslmflm' Twenty-five (25) parts of the 85/15 butsdienelll-ethyl-z-vinyl pyridine eopolymer (IsolstedtromthelstexotlnmpieVlI-Abythe edditlonotasuitableeuasuimztsuehmethyl aleoholoranaqueoussoluflonoiaeebioeeidsnd m r la mredins mmmm dlmltngundsqueeadng The to'lhis blend is applied by of dried ten minutes at 135 otanaeeelerstor lortheresin adhesive is heat-converted. iflpurisofbutonohlsaddedand thenremmedtrom .driedend bondaobtainedareshownesihmflin'lablen.

Table II nonnmo or NYLON name T0 immune lbdllellnhldlllildmhm auamammuemauuaaanm I I l 111 Illl l aaumueamanammnumum im ueopolym-l-ilhi? (mom) mour- Rubber.

Bubbs.

In'r'.

3-1.2 Rubbl'. FOB-8.-. {Babb-2 Rubber. eopolymu-i-pbmoliemdn (cement) I H resin (Inn lurmeldehyde ruin E 3 42 emsm: we

pyridine praise and of tests 0! adhesive shown in Table in.

6 bu (Example indieotesiblluleolstoekntherthnsdhedve.

nae tollowina exemplu illustrate the improved m iti m efl'ect obtained by utllislnz a blend of natural rubber with a dime/vinyl pyridine eopolymer Included for eompeflson are adhesive values andathermoeettinzphenolaldehydereein. obtainedbothcuredandunwred The "green (uneuredi sdheeinn to rubber of theeompositionaboveisshownbymummltesb- 70 ingtobei'arbetterthanflmtotnsimihroom- EXAMPLE!!! Amixtureotmpertsotbutadieneandmperts o! 2-vinyl pyridine is emulsified in 157 parts of position without the natural rubber latex. The

an aqueous sol eontsininumofwdium foliowingbestlsusedtoobtalnquantltativemees- 01000919 118 1 lodlllm 'q m urementsoi'zrem"adheeionintheenmplesbedium hydroxide, 1 part oi. a formaldehyde/so m Theedbesiveoompositlontobeteetedisspp1iedtoa8inehby2inehstrlpoteloeewoven dium naphthalene suii'onate condensation prod? uet,lpo.rtotnotusiumpersuiiotemd0.1part v nylon fabric and the coated material dried in an oven for from live minutes at 100 C. to ten minutes at 135 C. This immesnated' material is allowed to cool and is then applied to a 1 inch by 1.5 inch strip of uncured compounded rubber stock from which a holland cloth protective coating has just been removed after warming the stock to 100 C. A thin glass cover is placed on the fabric and the assembly together while the rubber stock cools. under a five pound prwsure for five minutes. The weight and cover glass are then removed, the fabric-rubber laminate aged sixteen hours and the pull required to separate the rubber and fabric measured in grams per inch.

In a manner similar to that of Example XII-B, 75:25, 50:50 and 40:00 mixtures (on a dry basis) oi'pa 90/10 butadiene/il-vinylpyridine copolymer prepared in the manner of Example XII-A and natural rubber latex were blended in approximately a 3.5: 1 ratio of total rubber resin formers with a 1/0.'! (molar) resorcinol/formaldehyde rzxamxv A solution of 2.3 parts of resorcinol, 1.8 parts of 37% formaldehyde solution and 1.1 parts of aqueous 10% sodium hydroxide solution in 25 parts of water is added slowly, with agitation, to a preformed blend of 12 parts of concentrated natural rubber later (60% solids), 10 parts of the 85/15 butadiene/5-ethyl-2-vinylpyridine eopolymer latex prepared as described in Example x-A, and parts of water. The resulting composition is applied to nylon fabric and tested for both cured and "green" adhesion as described in Example XII. The "green adhesion is equivalent to that of item 4 in Table III. The cured bond between nylon fabric and rubber is over fiity pounds per inch at C. and exceeds the tear strength of the rubber at 95 C. The bond to GR-S exceeds the tear strength of the vulcanizate at both 25 and 95 C.

A control adhesive made up as described in Example 1: without natural rubber latex. gives equally excellent cured bonds. but the green adhesion is inferior, approximately equal to resol prepared by mixing the ingredients as dethat of item 5 in Table III. Table III ADHEBION' OF NYLON FABRIC T0 BUBBEBS Omed Adhesion LbJIn.

Gr Adh 1 Adhesive To Rubber To GB-B 'l" ll.ubbe1 In. at 25 0.

l 77 B lpyridine co lymer (00/10 2B 2B 55 '10 B tterthan 1 natural to]? glue resorcinonnd formald yde zltem 5). contra (Example III). 2 blend xnmplex 00 142 I95 I 50:50blm1d mmplex 40 32 61 32 850. 4 40:50 blend Example XIII 48 03 la) 3,7003 5 00/10 bu ggllnylpyridlne plus resorcinol/ i5 85 23 150. 0 Rubber lotexlresordn olliormaldehyde resol 1s 10 as 1 20 8,000.

1 Indicates failure of cured rubber stock rather than adhesive Fallure, at least in part, of uncured rubber stock rather than adhesive.

III.

XIV

A solution of 2.3 parts of resorcinol, 1.7 parts of a 87% formaldehyde solution and 1.1 parts of The following example is directed to copoly- 45 mers of 2-methyl-5-vinylpyridine and a diene.

aqueous 10% sodium hydroxide solution in 25 7 parts of distilled water is added slowly, with stirring, to a preformed blend of 12 parts of natural rubber latex concentrate (10% solids), 13.3 parts of an /15 butadienelz-vinylpyridine copolymer latex containing about 40% solids and prepared in a manner similar to that of Example XII-A, and 25 parts of distilled water.

The resulting composition is tested exactly as described in Example XII as an agent for bonding nylon fabric to rubbers. Cured bonds at 20 C. of over fifty pounds per inch between the fabric and Glt-B or rubber were obtained. At 95 0., the adhesion exceeded the tear strengths oi the vulcanizates.

The "green" adhesion of this composition is demonstrated by manual tests to be fully equivalent to that of the adhesive based on the 60/40 blend of natural rubber and the 90/10 butadiene/vinylpyridine copolymer of Example XIII (Table III, item 4). The gree adhesion of a control adhesive made up according to Example together with resols:

EXAM-E XVI 2-methyl-5-vinylpyridine (a methyl-substituted beta-vinylpyridine) is prepared by treating 5-ethyl-2-methylpyridine with chlorine. treating the resulting 5-(alpha-chloroethyD-2-methylrldine with sodium acetate and pyrolyzing the resulting acetate. schematically, the reactions are as follows:

N\ 01 raccoon.

OC-CH:

A mixture of 45 parts of butadienc, 15 parts of 2-methyl-5-vinylpyridine and 1.2 parts of rosin IV is markedly inferior and is about equivalent to 75. is emulsified in 80 parts of a solution prepared thatofitem5inTableIlI.

by dissolving 15.6 parts of sodium hydroxide.

assure ll tflpartsotoleicacidJflpaflsoiil mum naphthalene sullonate condensation solution composed oi 2 parts oi resorcinol, oi'al0% aoueoussolutionoisodiumhydroxide. 1.05 parts oi 37% aqueous iormaldebyde, and or water is added slowly, with stirring. to 20 parts of the it/25 butadiene/fl-methyl-b-vinylpyridlne copolymer prepared asdescribedabove. Theblendisdilutedwithm 01 water. After as'lna ior twenty-four at room temperature, the blend is applied nvlontabrlcandtestedasanadhesive inBxample I. at 20" 0., bonds oi forty threepoundsperinehareobtainedreapectively,betweentheiabric andGlt-Bandbetweenthe labric and natural rubber. At 05 0.,

Thecompositionoltheelastomerstoeksof natural rubber and synthetic rubber (GR-8) used I intheaboveeramplesisset'forthintheiollom' in; table.

Table IV us run OABOABB s'rocxs snrLoYsp ma 3 To nonnmo The invention broadly comprehends blends of any vinylpyrldlne/diene hydrocarbon and any phenol-aldehyde heat convertible resol. By phenolmm heat convertible resol is meant any tion product oi an aldehyde with a monomeric phenol which, under the influence or heat. becomes permanently iniusible; these thermosetting condensation products are generally resinous in character.

The above examples specifically disclose, for

forming the vinylpyridine/diene hydrocarbon copolymer, alpha-vinylpyridine (in which the pyridine ring is unsubstituted except for the vinyl group), b-ethyl-z-vinylpyridine and z-methy B-vinylpyridine. However, the invention broadly comprehends, for the production oi the vinylpyridhlc/diene hydrocarbon copolylner, the use of alpha, beta and gamma vinylpyridines and their homologues, e. g. 5-ethyl-2-vinylpyridine,

5-propyl-2-viny1 pyridine. 5-miyl-2-vinyipyridine, i-hexyl-il-vinylpyridine. 5-heptyl-2-vinylpyridine, 0 methyl 2 vinylpyridine, 4,0 dimethyl-2-vinylpyridine,2 -methyl-5-vinylpyridine, Z-methyl-i-vinylpyrldine and other alkyl substituted vinylpyridlnes. Alpha vinylpyridine (Z-vinylpyridine), 2 methyl 5 vinyloopolymer pyridine and 5-ethyl-2-vlnylpyrldine are pre terred 'lhe invention contemplates for use in the preparation of vinylpyridine/diene hydrocarbon eopolymersany dlene hydrocarbon. particularly poiymerisable coniusated double bondsie. g. lz-butadiene. isoprene, dimethylbutadlene or piperylene: or these, butadiene and hoprene are preferred. not only became of their low cost and availability, but also because or the readiness with which they copolymerlae with vinylpyridines to give prod- The diene hydrocarbon vinyl pyridine ratio of thecopolymeroperableinthb inventioncan bevariedoverwidelimits. For mostpmposes, particularly in bondinafabrics to rubbers, a pliable composition having rubber-like characteristics is preferred. Good results are obtainedwithcopolymersinwhichwfii tofl'ikoi the total is diene hydrocarbon; in general, those productsconsistinol05% to'm'itdieneandthe remainder a vlnylpyrldine are preferred. Three component copolymers containing at least 50% diene and 5% of a vinylpyridine, the remainder consistirm of other vinyl or vinylidene compounds orbutenedioicaciikoresterasuehasstyrene, dimethyi (vinylethinyl) carbinol, vinylldene chloride. methyl vinyl ketohe. vinyl naphthalene, methyl methacrylate, acrylonitrile or diethyl iumarateandthelikearealsooperableandare included.

In forming the diene hydrocarbon-vinylpyridinecopolymenapflpreierablylneacessoi 7.0isused,thepHatthehesinningo1the copolymerisatlon preferably being 10.0 to 12.0. Also.altho|mhitispreierredtousetheaqueous emulsion method for iormin: the diene hydrocarbon/vlnylpyridine. copolymer, one may dissolve the and elect the reaction in solution. or one may merely mix the monomers in bulk (without solvent or dispersing medium) and cause the reaction to proceed. Example I-A illustrates a typical method iorpreparine thecopolymerinanaoueousmedimbutthe oonditionscamofcourse,bevarledinaooord- :tce with thehlowledseoi those skilled'in the It will be understood however that the invention is not limited as to the manner or conditions or preparin: the diene/vinylpyridine copolvmer. Thus, in place oi-sodium oleate, one may use other alkaline agents such as alkali metal or ammonium, or substituted ammonium salts of lon.chain carbosylic acids such as oleic acid or rosin. e. g. potassium oleate and sodium resinate, long chain sullonic acids. salts of ions chainbetaineaoraaltsoiion ehainaicoholsulrates, or combinatiom or any or these dispersing scents, alkali metal or ammonium oleates, roslnates or sulfonates beingprei'erred. In place or the formaldehyde/sodium mphthalenesulinnate condensation product described above and which iunetionsto add stability to the emulsion. onemayuseotherwellknownprotectivecoiloids. While emulsion systems are in general preferred for convenience in preparing aqueous adhesive formulations, onemay use bulk, solution or granulation polymerisation techniques. Suitable po initiators or catalysts include peroxides such as bensoyl peroxide, lauroyl peroxide and hydrogen peroxide, inorpanic per such as alkali metal pertee and persulrates, potamium persull'ate being the preferred polymerisation initiator. In place of potassium i'erricyanide which functions to activate the catalytic action of the potassium persulfate used in the examples, one may use other catalyst activators such as alkali metal ferrocyanides and readily oxidizable sulioxy compounds such as sodium hydrosulflte, sodium bisulflte. sodium pyrosulfltc and the like. Where an organic peroxide such as benaoyl peroxide is used, activators are normally not used.

The use of modifiers such as carbon tetrachloride, 5,5,5-trichloroamyl mercaptan and long chain unsubstituted mercaptans such as the lauryl mereaptan (dodecanethiol) oi Example I-A, octyl and decyl mercaptans or other commercially available mercaptans predominating in octyl, decyl and higher mercaptans, dialkyl xanthogen disulfides, sulfur and other modifiers, is optional in the polymerimtion mixture, but is preferred because of the improved green adhesion or ability to hold the lamination securely in place before the rubber stock is cured.

The polymerization temeprature may be varied within wide limits, for example to 100 C., but in general temperatures of 30" to 60 C. are preferred. The time required to obtain a high yield of polymerizate will depend on the temperature, catalyst and system, e. g. emulsion system, used. The reaction time may be much greater or less than twenty hours, a shorter period ordinarily being used,where the reaction is carried out at the higher temperatures.

The smooth latex resulting from polymerization may be stabilized in any convenient manner. The addition of an aromatic amine, preferably in the form of a dispersion, e. g. phenyl-alphanaphthylamine or the phenyl-alpha-naphthylamine-diphenylamine 01' Example I-A. serves to stabilize the rubber in the latex or aqueous dispersion until it is ready to be used.

In place of formaldehyde, there can be used for the preparation at the heat convertible resols other aldehydes and materials which, under the conditions of reaction, liberate formaldehyde in the preparation of the thermosetting aldehyde resols. Examples oi such materials are paraformaldehyde, hexamethylenetetramine, acetaldehyde, butyraldehyde, chloral, furfural and salicylaldehyde; formaldehyde, or materials which readily liberate formaldehyde, are preferred.

The phenols used for the preparation of the thermosetting aldehyde-phenol resol can be monohydric or polyhydric phenols or mixtures of these. Examples of monohydric phenols are phenol, the cresols, the xylenols and the naphthols, and their condensation products with aldehydcs or ketones, e. g. diphenylolmethane or diphenylolpropane; halogenor alkyl-substituted phenols such as chlorophenols, tertiary butyl phenol and tertiary-amyl phenol. Ex-

- amples of polyhydric phenols are resorcinol,

catechol, phloroglucinol, orcinol and hydroquinone as well as natural products containing poiyhydrlc phenolic groups such as quebracho extract. The preferred phenols are the mononuclear polyhydric phenols, particularly resorcinol, since they provide. in general, superior adhesion.

The particular resins most useful in the practice of the invention are heat convertible resorcinol/i'ormaldehyde resols. The thermosetting resorcinol/formaldehyde resol may be made of mixtures having resorcinol/formaldehyde mol ratios of from 3:1 to 1:10. In general. those containing about 0.7 to three mole of formaldehyde per mol of resorcinol are preferred. Aidehyde liberating su such as hexamethylenetetramine may be employed to replace part of the aldehyde, but, in general, it is preferred to operate without them.

The inclusion of rubber latex, together with the diene/vinylpyridlne copolymer and thermosetting resol is of particular advantage in view of the excellent adhesion eiiected by such compositions before curing o! the rubber ("green adhesion) as well as good flnal (cured) adhesion. any good quality natural rubber may be used for this purpose, Hevea rubber latex, either normal, dilute or concentrated, being preferred for the preferred aqueous adhesion systems.

The amount of natural rubber latex used in admixture with the copolymer, depending on the amount of green adhesion desired, may vary from 5% to of the combined natural rubber and copolymer with little or no loss in cured adhesion. Compositions containing from 30% to 70% of natural rubber latex are in general preferred. Amounts below 30% give only minor improvements in green adhesion over similar compositions without rubber latex, which improvements are frequently not satisfactory for many processing operations. It more than 70% of natural rubber latex be used, somewhat lower cured bonds will result at the low adhesive loadings which give excellent results with compositions containing less natural rubber. Particularly noteworthy is the large increase in green adhesion obtained by increasing the amount or natural rubber from 50% to 60% (items 3 and 4 in Table III), almost up to the level of compositions containing only rubber latex with the resorcinol/formaldehyde resin. This great increase in green adhesion is made without any serious loss in cured bond strength over the 50:50 natural rubber/copolymer composition, or even over compositions containing only copolymer, resorcinol and formaldehyde, which is a surprising and unpredictable result.

In the practice of this invention, blends of the diene hydrocarbon/vinylpyridine copolymer and the resin containing from 10% to resin may be employed. In general, for tire cord application, it is preferred to operate within the range of 20% to 60% resin, particularly from 25% to 40% resin. It is also preierred to use the adhesive in the alkaline state, i. e. at a pH above 7.0.

In addition to the copolymer, resin. rubber and the other materials discussed above as suitable addition agents. the adhesive composition may contain fillers such as carbon black, vulcanizing and compounding ingredients such as sulfur, zinc oxide, rubber accelerators, softeners, plasticizers, tack producing agents other than natural rubher and the like, suitably dispersed or dissolved in the blend. V The use of an aqueous system for the blending and practical application of the adhesive is preferred for convenience and economy. Soluttions or dispersions of the copoiymer and the resin in suitable organic solvents such as toluene, toluene-ethyl alcohol mixtures, or chlorinated aliphatics however may be used.

As illustrated in the examples, the resorcinol/formaldehyde component or resol may be prepared by the simple solution of the resorcinol and formaldehyde in water or an alkaline material such as sodium hydroxide may be added for r the purpose of advancing the condensation which proceeds readily in alkaline solution; Alvely. as pointed out in Example II and other examples, the resol may be formed by addme the phenol and aldehyde to the butadiene/vinylpyridine emulsion as in Example II. preferably in the presence of sodium hydroxide or equivalent alkali. The sodium dibutyl dithiocarbamate used in Example II and in other examples functions as a vulcanization accelerator. but its presence is entirely optional especially since the accelerator in the rubber stock in all probability migrates to the adhesive.

The lamination procedure may be varied considerably. Generally speaking however, the temperature used for curing the thermosetting resoi is about 100 to 200' C. and where the lamina tion involves the plying of the rubber to other things such as metal, cotton or synthetic fibers for example, the unvulcanised rubber stock will be vulcanized at a temperature within this range, thereby making a separate heating step for converting the resin to the iniusible state. By proper formulation oi the rubber stock and adhesive, the compositions can be made to linninate at ordinary temperatures. It is preferred that the adhesive be dried as described in Example 1-0 after its application to one of the elements to be laminated and before the second element to bc'laminated is brought intocontact with the element containing the adhesive. Also, an improvement in bond strength is noted when either the resol solution or the I blend of diene hydrocarbon/vinylpyridine and resol is set aside to age for a period before application as an adhesive; as is described in Example VII, this aging period may be twenty hours. but a greater or less period, c. g. one hour up to forty-eight hours may be used with advantage. 'lhis aging period is particularly beneflciai where the resol comprises resorcinol to formaldehyde in the moi ratio of 1:0.1.

As will be noted from the above description, the compositions of this invention, when used as adhesives, provide an excellent bond not only at ordinary temperatures. but also at elevated tempcratm'es.

While the adhesive is particularly suitedior bonding cotton, viscose rayon and nylon fabrics to rubbers such as natural rubber, Git-S, neoprene, butadiene/acrylonitrile rubber and other diene rubbers as in the manufacture arenas I 16 i I claim:

1. an a copolymer of a diene coniugated double "bondsandaoitheclassconsistingoi of tires, belts, coated fabrics and other articles, it

may be used in other applications such as bonding metals, wood, paper, ceramics, glass, leather or plastics to each other or to rubber. In view of the great utility of the compositions embodied in the present invention for improving adhesion, this phase of the invention has been particularly emphasized, but it will be understood that the novel compositions may also be used generally as nim-iorming components of coating compositions and as binders in molding comp itions.

The term copolymer" as used herein signifies a polymer containing in its polymer molecule units oi more than one monomeric material, e. g. the polymer obtained by polymerizing together both monomeric vinyipyridine and monomeric butadiene; the term is not intended to include physical mixtures or diiferent polymers.

The practice of the invention is capable of considerable modification and arm variation which conforms to the principles or the invention isainmotendedtobeincludedwithinthescopeofthe cl unsubstituted moncvinylpyridines and alki i substituted monovhiylpyrldincs. the said hydrocarbon being present in amounts or 50% to by weight of said and the vinyipyridine being present in amounts at least 5% by weight of said copoiymer in admixture with a heat convertible polyhydric de resol, the amount of said resol in said adhesive being from 20% to 60% by weightoi said adhesive. 7

mhnadhesiveacopolymerora diene hydrocarbon containing coniusflted double bonds and a member of the class consisting of unsubstituted u i a and allryl substituted monovinylpyridines, the said hydrocarbon being present in amounts or 50% to 95% by weight or said copolymer and the vinylpyridine being present in amounts at least 5% by weight of said oop lymer in admixture with a heat convertibie resorcinol-aldenvde resol, the amount of said resolinsaid adhesivebeingfrom20% to60% by weight of said adhesive.

8. Anadhesiveacopolymerofabutadiene containing conius ted doublebondsand amemberoitheclass consistingoi unsubstituted monovinylpyrldines and alkyl substituted monovinylpyrldines, the said hydrocarbon being present in amounts or 50% to 95%-by weight of said copolymer and the vinylpyrldine bemgpresentinamountsatleastfiqt byweightof said in admixture with a heat convertible resorcinol-aldehyde rceol, the amount of said resolinsaidadhesivebeingfromflfi to6096 by weight of said 4. A laminated artlclecomprlsing a solid materialbondedtoasolidmaterialbyanadhesive comprisedor a otadiene hydrocarbon containing conjugated double bonds and a member of the class of unsubstituted monovinyipyridines and alkyl substituted monovinyipyridincathesaidhydm 'bonbeingpresentin amounts or 50% to 96% by weight of said copolymerand the vinylpyridine being present in amounts at least 5% by weight oi said copolymer in admixture with an ini'usible polyhydric phenolaldehyde resin formed from a heat convertible resin previously blended with said copoiymer, the amountofsaidresinbeingfrommfi to60% by weight of said adhesive.

danarticleinaccordancewlthciaimiin which the said resin is a resorcinol-aldehyde 8.Anarticlelnaccordancewithclaim4in which a material is bonded to an elastomer by said adhesive.

'LAnsrticleinwithclaimiln whichaiibrousmaterialisbondedtoanelastomer by said ve.

B. A laminated article comprising a solid material bonded to a solid material by an adhesive com osed of a butadiene/vinyi pyridine copolymer in which butadiene makes up 50% to 95% of said copolymer and the vinylpyridine being present in amounts at least 5% by weight of said copolymer in admixture with a resorcinol-aldehyde resin formedfrom a heat-convertible resin previously blended with said copolymer, the resorcinol/aldehyde mol ratios in said resin bein from 3:1 to 1:10 and the amount of saidresin being iron 20% to 60% by weight of said adheis sive.

9. A laminated article in accordance with claim 8 in which said vinylpyridine is 2-vinyipyridme.

0. A laminated article in accordance with claim 8 in which the said aldehyde is formaldehy e.

11. In laminates, a composition comprising a copolymer 01' a diene hydrocarbon containing con- Jugated double bonds and a member of the class consisting of unsubstituted monovinylpyridines and alkyl substituted monovinylpyridines, the said hydrocarbon being present in amounts 01' 50% to 95% by weight oi said copolymer and the vinylpyridine being present in amounts at least 5% by weight 0! said copolymer in admixture with an infusibie poiyhydric phenol-aldehyde resin formed from a heat convertible resin previously blended with said copolymer, the amount of said resin being from 20% to 60% by weight of said adhesive.

12. A composition in accordance with claim 11 in which said intusible resin is derived from a resorcinoi-aidehyde resin.

13. A composition in accordance with claim 11 in which said copolymer is a butadiene/vinyipyri- 18 dine copolymer and said iniusibie resin is derived from a resorcinoi-iormaidehyde resin.

CHARLES J. MIGHTON.

REFERENCES CITED The following references are of record in the file oi. this patent:

UNITED STATES PATENTS Number Name Date 1,849,109 Novotny Mar. 15, 1932 2,128,635 Charch Aug. 30, 1938 2,255,834 Taylor et ai Sept. 16, 1941 2,277,941 Almy Mar. 31, 1942 2,291,208 Brown et a1 July 28, 1942 2,334,526 Allison Nov, 16, 1943 2,394,375 Gross Feb. 5, 19 6 2,402,020 Cisiak June 11, 1946 2,405,038 Jennings July 30, 1946 2,429,397 Compton et al. Oct. 21. 1947 FOREIGN PATENTS Number Country Date France Aug. 7, 1939 

4. A LAMINATED ARTICLE COMPRISING A SOLID MATERIAL BONDED TO A SOLID MATERIAL BY AN ADHESIVE COMRPISED OF A COPOLYMER OF A DIENE HYDROCARBON CONTAINING CONJUGATED DOUBLE BONDS AND A MEMBER OF THE CLASS CONSISTING OF UNSUBSTITUTED MONOVINYLPYRIDINES AND ALKYL SUBSTITUTED MONOVINYLPYRIDINES, THE SAID HYDROCARBON BEING PRESENT IN AMOUNTS OF 50% TO 95% BY WEIGHT OF SAID COPOLYMER AND THE VINYLPYRIDINE BEING PRESENT IN AMOUNTS AT LEAST 5% BY WEIGTH OF SAID COPOLYMER IN ADMIXTURE WITH AN INFUSIBLE POLYHYDRIC PHENOLALDEHYDE RESIN FORMED FROM A HEAT CONVERTIBLE RESIN PREVIOUSLY BLENDED WITH SAID COPOLYMER, THE AMOUNT OF SAID RESIN BEING FROM 20% TO 60% BY WEIGHT OF SAID ADHESIVE.
 7. AN ARTICLE IN ACCORDANCE WITH CLAIM 4 IN WHICH A FIBROUS MATERIAL IS BONDED TO AN ELASTOMER BY SAID ADHESIVE. 